1. Field of the Invention
This invention relates to improved methods of preventing the production of sand with well fluids, and more particularly, to such methods utilizing a hardened open cell foam as a sand screen.
2. Description of the Prior Art
Oil and gas wells are often completed in unconsolidated formations containing loose or incompetent sands which migrate with produced fluids. The presence of sand particles in the produced fluids is undesirable in that the particles abrade pumping and other producing equipment and generally reduce the fluid production capability of the formations. Incompetent subterranean formations include those which contain loose sands that are readily entrained by produced fluids and those wherein the sand particles making up the formations are bonded together with insufficient bond strength to withstand the forces produced by the intermittent production of fluids from the formations.
Heretofore, unconsolidated formations have been treated by creating fractures in the formations and depositing proppant material, e.g., sand of a selected size, in the fractures to maintain them in open positions. In addition, the proppant has heretofore been consolidated within the fractures into hard permeable masses to prevent it from flowing back and to reduce the migration of sand through the fractures with produced fluids. Further, costly gravel packs which include sand screens and the like have been installed in wells which serve as filters and prevent formation sand and/or proppant from migrating with produced fluids into the well bores. However, since gravel packs, sand screens and the like filter out sand, the presence of the filtered sand can add to the flow resistance thereby producing additional pressure draw down which causes the fracture faces and other portions of the formation to break down and consolidated proppant and sand in fractures, gravel packs and the like to be bypassed.
In horizontal well bores formed in unconsolidated formations, the well bores are often completed open hole and a slotted liner, sand control screen, gravel pack or the like is installed in the well bore. Again, however, as the incompetent formation breaks down from being produced, the slotted liner, sand control screen or gravel pack is often bypassed whereby formation sand is produced along with formation fluids. Thus, there is a need for improved methods of completing unconsolidated producing formations whereby sand production with produced fluids is prevented.